The invention pertains to a detachable coupling for pressure-medium-filled HF lines with longitudinally sealed shielding at the line ends.
Such couplings are required in cavity-insulated coaxial lines and high-frequency hollow waveguides which for a variety of reasons are operated with an excess inner pressure. As pressure medium, either dried air or a gas can be used. The air is produced by a corresponding ventilating apparatus and as gas nitrogen or sulphur hexafluoride and similar gases are often used. The ventilation systems themselves ensure constant pressure in the line system.
To supply the gas to the high-frequency line, coaxial connectors are provided with a gas connection bore. Waveguide sections are provided with their own gas injection member. In semiflexible waveguides (oval hollow waveguides) the air injection member is usually combined with the end fitting which simultaneously effects the transformation to the standardized rectangular or circular waveguide. All these fittings require their own supply line for the protective gas, usually in the form of thin copper or aluminium tubes or in the form of hoses. For transporting such lines, frequently a valve is inserted in the filling opening and before transport the lines are pumped up and sent under excess pressure. At the place of use, by suitable lines the air supply or gas supply must be insured.
For certain purposes it is frequently necessary to release and reconnect such couplings lying in coaxial lines. This means that the protective gas can escape and air and moisture can penetrate into the lines. To avoid this, at the ends adjoining the coupling longitudinally sealed means have been provided. However, this interrupts the connection for the protective gas or air in the connected condition. Consequently, at the coupling points bypass lines have been provided which on decoupling or establishment of the coupling had to be separately released or reconnected, a danger of protective gas escaping again existing.
The problem underlying the invention is therefore to ensure the gas connection of the individual line sections via the couplings without using bypass lines, satisfactory sealing being guaranteed after release of the couplings.